Magazine Archive

Article Group:Computer Musician

BBC Micro Music

The past few months has seen an explosion of music programmes for the BBC Micro, so we thought it'd be fun to take a number of these beasties and put them under the dissection microscope in this month's 'Round-Up'.

On the face of it, the BBC Micro should be no better than any other micro with a sound chip on the motherboard that's doing its darndest to be a kazoo. But the beauty of the music side of this machine is that the operating system designers used their noggins when it came to constructing the interface between us users and the sound chip itself. Those SOUND and ENVELOPE statements might appear a cunning means of persuading computer journalists to right screeds about the machine, by way of explaining what all those parameters actually do, but there's rhyme and reason in them there numbers, and it all comes down to making the sound chip more musical than you might otherwise imagine. On to the programs...

QUICKSILVA MUSIC PROCESSOR

(Model A/B, cassette, £14.95)

Quicksilva have a high reputation for quality software, and, looking at their BBC Music Processor (MuProc), it's not hard to see why.

Basically, MuProc sets out to simulate the operation of a synthesiser, 4-track recorder, and mixing desk, by providing over 30 single-key functions for envelope selection and modification, sound effects, tape controls, mixing editing, and so on.

MuProc's ingenious display.

A single MODE 7 display is used which packs a lot of information into a tight space. Tape controls are on the right, with a 3-position digital counter for tape position and drive indicators for playback, record, reverse, fast forwards, and single-stepping (both ways!).

Music can only be entered from the qwerty keyboards, using one row from '1' to '£' as the first just-under-two-octaves and another from 'A' to 'X' as the top end of the keyboard. Personally, I think it's a bit obtuse putting the lower part of the keyboard on top of the higher part, but I suppose you get used to it. Bearing in mind that MuProc doesn't provide any visual assistance to avoid getting fingers in a twist, an alternative coded, or MCL, form of music entry would have been useful.

Where MuProc scores is in the ability to add expression to a piece of recorded music. Because envelope details are stored and displayed independently for each and every note, any number of envelope changes can be entered at the editing stage. To make life simpler, MuProc simplifies the 14 ENVELOPE statement parameters down to just 5, for a) pre-defining the amplitude part of the envelope, b) altering the sustain, c) pre-defining the pitch offset, d) modifying the pitch offset, and e) adjusting the overall volume. What's more, these envelope changes are displayed for each part as it's playing back (from the left to the centre of the display).

When music is entered into memory from the keyboards, 10 bytes are required for each note, which translates into around 1,950 notes for a 32K machine. Using the 'long-play' feature, this bytes/note requirement is reduced to 6 by putting notes into playing order and eliminating pointers, thereby increasing the note storage up to 3,250.

All of MuProc's ingenious envelope changing features are demonstrated by one of the examples provided on tape — the first movement of Bach's 2nd Brandenberg Concerto. In other hands, this might have been yet another bit of sewing machine counterpoint, but, here, it really becomes something else. In fact, there's well over 100 envelope changes during the course of the piece, and, judging by an infamous 'plopping' sound that appears towards the end, it'd appear that someone's trying to beat Wendy Carlos at her own game! Mind you, I wonder whether all those notes were entered from the Beeb's qwerty keyboard? Somehow, I doubt it!

CLARES BEEBSYNTH

(Model B, cassette (£7.95) or disk (£10.95)

Clare's Beebsynth is much less ambitious than MuProc, but it's also half the cost. Its angle is also somewhat different to MuProc in that it concentrates its attention on making the best of a bad job, ie., using the qwerty keyboard as a live music input device. And, whilst MuProc certainly falls flat on its face as far as that's concerned, Beebsynth makes a reasonable stab at it.

Clare's envelope definer.

Basically, there are two sides to using it: firstly, the envelope definitions — filling in the parameters of the ENVELOPE statement — which is accomplished fairly painlessly with cursor keys and a rather basic display (no graphics to show the shape of the envelope); and secondly, the keyboard input itself which uses a different and more useful display.

Rather than doing a MuProc double manual act, Clare's have managed to get 2 octaves out of the middle two rows of keys from 'CTRL' to 'RTN', with visual feedback provided by a set of displayed piano keys. The trouble with both this display and the similar one in Musicsoft's Synth is that they just sit there looking (fairly) pretty, passive as a, er, pork pie. I think keyboard displays should be made to work for their share of the screen, and some form of registering of finger activity (blobs appearing inside relevant keys, for instance) wouldn't go amiss in the pursuit of micro music excellence.

Clare's keyboard display.

Various types of keyboard scanning (last note priority, etc.) can be put into effect with three of the function keys. All this works pretty well, and one ends up with a fairly playable keyboard with 3-voice polyphony. Mind you, both this program and all the others in this review would benefit greatly if some bright spark could come up with some sort of overlay that made the keyboard look a bit more like the real thing. Wishful thinking, I guess...

One drawback is that all 3 voices are assigned the same envelope — some sort of keyboard split would be a useful feature — but, more annoyingly, it's not possible to switch to a different envelope without going to a different display. That needs changing, I think.

A rather nice touch is the pitch bend facility provided by using the up and down cursor keys. Using these is actually quite like a pitch bend wheel, though not quite as fast as one might like, but it's still a useful feature.

Conclusions: A fair program, but the user interface needs a bit more work.

MUSICSOFT SYNTH

(Model B, cassette, £8.50)

Musicsoft's Synth is the most recent of the music programmes in this review. In fact, the author very kindly rushed us a pre-production copy specifically for the review, so certain features may change by the time it sees the commercial light of day. As far as comparisons with MuProc and Beebsynth are concerned, Synth would seem to offer the best of both worlds, in that it provides reasonably efficient input from the qwerty keyboard and a number of rather ingenious recording and editing features.

Recording with Musicsoft's Synth.

This time, the rows of playable keys stretches from 'TAB' on the left to the cursor key on the right — a stretch of 2 octaves-and-a-tone. Selecting the 'record' option from the main menu allows one to lay down a track for one of the four sound channels. Unlike some other real-time input programs, recording with Synth also provides most of the benefits of 'event' recording. So, for instance, as you're recording, you an change the volume setting (actually, the ALD parameter in the ENVELOPE statement), add pitch bend up or down, switch between envelopes, or even change any of the ENVELOPE parameters, and all this will be stored in memory. You're also able to stop recording at any point to back track to an incorrect event, change it, and then continue from where you left off.

Playback can either be with the original timing or using the 'alter rhythm' feature. This is rather like the 'one-key play' mode of certain Casio keyboards and allows one to correct timing discrepancies, or change them completely, simply by trotting out recorded events with key taps. This 'adjusted' real-time performance can then be used for putting more tracks on top or it can be trotted out all over again if you still haven't got it right!

Another rather ingenious facility is the 'bring in line' feature that automatically lines up channels 2, 3 and 0 with channel 1 if they are within about 15/100 of a second when using 'alter rhythm'. If this is done with the speed slowed down, then the timing latitude is greater because the bringing-in-line is tempo related. Of course, it could be argued that it's the timing inconsistencies that add human feel to micro music, but, given the limitations of the keyboard input situation with the BBC Micro, this seems a sensible idea in this instance.

Finally, there's a 'repeat' facility which allows you to specify repeats for ranges of stored events. In effect, this means you can put any section of notes anywhere — even putting a beginning section at the end — and then reassemble things later on. Also, this extends to apparent event storage from around 3,000 notes to something a good deal less limited. These repeats can also be stored on tape along with the events themselves.

Conclusions: the display and interactive side needs a bit of working on to bring it up to the standards of MuProc, but it's basically a very flexible and inventive program that's highly recommendable.

Musicsoft also produce an excellent 'Musictools 1' cassette (for £5.75) which is aimed more at the educational market and general user. This includes a monophonic recording keyboard with speed, pitch and rhythm alteration on playback, a simple auto-tune generator, a symbol writer to generate chunky musical graphics (very useful for classroom teaching), and a program for cursor-editing of ENVELOPE statement parameters. All these programs are based on easily listable and movable PROCs, and the author suggests using them in different contexts on a mix 'n' match basis. All in all, rather good value!

BUG-BYTE BBC MUSIC SYNTHESISER

(Model A/B, cassette, £9.50)

Bug-Byte's Music Synthesiser is definitely of the non-real-time sort — not a keyboard display in sight! The two main sections of the program are 'edit' and 'play'. Edit works for setting up both ENVELOPE statement parameters (extremely slow and tedious with no help from the cursor keys to scroll up and down or from one parameter to another) and inputting notes into each channel.

Bug-Byte's version of envelope defining.

The major drawback of the note input is that there's no facility provided to alter the duration of one note relative to another. It's really right back to the old analogue sequencer territory, here. There are, however, some useful features, such as 'repeat' (a sort of inpart subroutine) and 'transposition' (which applies to all the notes in a part). One can also make up 'sections' of notes which can then be assembled, on playback, into verse/chorus-type structures.

In comparison to MuProc and Synth, this program looks pretty pathetic. Those programs actually turn the BBC Micro into a decent sort of musical tool, which by virtue of the sophisticated editing and per-note parameter changing that they encourage, make the micro work hard for its share of the National Grid. With Bug-Byte's offering, one can imagine the Beeb's 6502 sitting back on its multiple pins counting silicon sheep jumping over logic gates for all the processing it's forced to do.

Auto-composition (of spelling mistakes ...).

Also on the cassette is an 'Auto-Composer' program. This works on the basis of using your entered weightings for all the major and minor chords to ring simple rock-like progressions. It's quite fun, really (for a wet afternoon), but that's about as far as it's going to get as a model of transition rules theory. Where this program really enters the realms of mind-bogglingness is in the spelling department. I mean, it's sort of understandable to mis-spell syncopation as 'syncapation' in the instructions on the cassette liner, but when the same word is mis-spelt in a different way ('sincapation') in the displayed text, sync spelt as 'sink', and chord as 'cord', it really makes you wonder...

Conclusions: needs starting again from scratch, and this time the picture on the cassette liner (rock keyboardist and concerto-playing pianist) might be made more representative of the program's contents.

So, what does this selection of programs hold for the BBC Micro user who's more serious in his musical inclinations than the average consumer? Well, to be honest, no one stands a bat's chance in hell of cutting an LP on a basic BBC Micro, but, what can help a lot is to get the sound chip talking directly to a mixing desk (if you're feeling grand) or your Hi-Fi (if you're being more realistic). One possible externalising add-on for the BBC Micro is 'Microvoc', a couple of speakers in Airbal-type spheres that are advertised as 'The Sound System for the BBC Micro'. Frankly, I can think of better ways to spend £22.50, but I guess it might suit some users. A much better ploy is to dig inside the BBC Micro and find a couple of solder pads marked 'PL16'. This is a couple of resistors away to the left of the 76489 sound chip (IC18) on the left side (or 'west', according to Acorn terminology!) of the motherboard underneath the keyboard. Taking an output from this gives a really clean 50 mV signal direct from the sound chip which can then be treated with chorus, echo, or whatever. In fact, this is the route that the BBC used for DI-ing sound on 'Making the Most of the Micro', and you can't get a better recommendation than that!